textproduct: Albany

SYNOPSIS

Above normal temperatures continue through Friday with a weakening coastal low slowly approaching tonight into Wednesday resulting a few light showers mainly south of I-90. Then, a moisture starved cold front on Friday ushers in breezy winds followed by cooler temperatures for Saturday. Temperatures trend warmer for the start of the new work week.

DISCUSSION

Our Rex Block begins to breakdown today as our ~590dam upper level anticyclone weakens as it shifts eastward out of the Great Lakes. This occurs while our vertically stacked coastal low currently seen on water vapor imagery off the mid-Atlantic coast slowly presses northward. Thus, initial sunshine today will become filtered through increasing cirrus clouds that gradually expand from south to north ahead of the approaching coastal low. Temperatures today once again rise above normal as deep boundary layer mixing in a dry environment with 850hPa isotherms +10C to +13C and insolation supports temperatures in the mid to upper 70s with even low 80s in the Upper Hudson Valley where more sunshine will likely occur. Cirrus clouds expands and thickens tonight as our coastal continues its slow approach.

As mid and upper level moisture increases, isolated to widely scattered showers on the northern periphery of the low start to impinge upon the mid-Hudson Valley and NW CT during the pre-dawn hours (09 - 12 UTC) and we continue to show slight chance POPs here which matches with the ECMWF ensemble and NBM probabilities. Previous model runs suggested the incoming coastal low would weaken enough during its approach that slight chance and low end chance POPs would mainly be confined to our far southern zones. While the highest confidence in measurable showers remains over southern zones (20-35%), latest trends suggest up to a 15% chance that isolated showers expand as far north as the I-90 corridor given that the low's 500hPa circulation remains closed through 00 Thurs. Otherwise, Wednesday will feature cloudier skies, especially from I-90 southward with more filtered sun to the north. Thus, high temperatures will fall a few degrees short compared to the days leading up to it with 70-80% chance that temperatures exceed 75 degrees north of I-90 with just 25-50% chance to the south where clouds will be thicker. Total QPF amounts remain low and will not put a dent in the ongoing rainfall deficit as there is just a 20-40% chance that total rainfall exceeds a tenth in the mid- Hudson Valley and NW CT and under 10% closer to I-90.

Rain showers diminish in coverage Wed night into early Thursday as the coastal low's 500hPa circulation opens up and exits into New England. Early clouds give way to increasing sun on Thursday as weak high pressure builds overhead. Slightly breezy westerly winds behind our departing coastal low enhances boundary layer mixing and supports above normal temperatures once again. In fact, there is a 70-90% chance that highs exceed 80 degrees in valley areas but nearly 0% chance to exceed 85. Thursday night. A more potent yet moisture starved cold front then marches south and eastward out of Canada late Thurs night into early Friday morning. A tightening pressure gradient in the wake of the boundary will likely support breezy winds on Friday with northwest flow ushering in a much drier air mass (PWATs near 0.5"). Thus, we trended dew points downwards using the NBM 10th percentile to show values falling into 30s/40s. Between the dry air mass (RH values 30-45%), recent stretch of dry weather, and slightly breezy winds, we will monitor the potential for enhanced fire spread on Friday. A ~1030hPa Canadian sfc high and upper level ridging build into the Northeast for Saturday, supporting abundant sunshine and ushering in a fall-like air mass. Morning lows on Saturday turn quite chilly with a 50 - 75% chance for lows in the southern and western Adirondacks to fall to 35 degree or lower so we will need to monitor frost potential. High pressure slides into New England for Sunday, promoting a southwest return flow and allowing tempertures to trend warmer for the new work week.

AVIATION /05Z TUESDAY THROUGH SATURDAY/

Through 06z/Wed...Mainly VFR conditions are expected through the upcoming TAF period. The exception would be if any fog develops prior to 12z/Tue. While latest satellite imagery shows a general lack of fog across the region, will maintain a TEMPO for brief IFR reductions at KGFL given a clear sky/calm wind in place. Some clouds lifting northward associated with a coastal low pressure system should prevent fog at KPSF. These clouds with the coastal low will be around the TAF sites on Tuesday but bases will remain in the VFR range. Fog is not expected to redevelop prior to 06z/Wed at any TAF site. Calm wind overnight will be variable at around 5 kt on Tuesday then trend light out of the southeast or calm Tuesday night.

Outlook...

Wednesday Night: No Operational Impact. NO SIG WX. Thursday: No Operational Impact. NO SIG WX. Thursday Night: No Operational Impact. NO SIG WX. Friday: No Operational Impact. NO SIG WX. Friday Night: No Operational Impact. NO SIG WX. Saturday: No Operational Impact. NO SIG WX. Saturday Night: No Operational Impact. NO SIG WX. Sunday: No Operational Impact. NO SIG WX.

ALY WATCHES/WARNINGS/ADVISORIES

CT...None. NY...None. MA...None. VT...None.